1. Field of the Invention
The present invention relates to the field of displaying technology, and in particular to a structure of a TFT (Thin-Film Transistor) array substrate.
2. The Related Arts
In the field of displaying technology, flat panel displays, such as liquid crystal displays (LCDs) and organic light-emitting diodes (OLEDs) have gradually taken the place of cathode ray tube (CRT) displays for wide applications in liquid crystal televisions, mobile phones, personal digital assistants (PDAs), digital cameras, computer monitors, and notebook computer screens.
A display panel is a major component of the LCDs and OLEDs. Both the LCD display panels and the OLED display panels comprise a thin-film transistor (TFT) array substrate. The TFT array substrate comprises a plurality of red (R), green (G), and blue (B) sub-pixels arranged in an array and a plurality of scan lines and a plurality of data lines. Each of the sub-pixels receives a scan signal from a corresponding scan line and a data signal from a corresponding data line in order to display an image.
FIG. 1 is a schematic view showing a conventional TFT array substrate. The conventional TFT array substrate comprises a plurality of vertical data lines that is arranged in order and parallel to each other, such as D1, D2, D3, D4, D5 and so on, and a plurality of horizontal scan line that is arranged in order and parallel to each other, such as G1, G2, G3, G4, G5 and so on, and sub-pixels that are arranged in an array. The sub-pixels that are arranged on the same row are each electrically connected via a TFT to the scan line located above the row of sub-pixels. For example, each of the sub-pixels that constitute a first row is electrically connected via a TFT to the scan line G1; each of the sub-pixels that constitute a second row is electrically connected via a TFT to the scan line G2; and so on. The sub-pixels that are arranged on the same column is electrically connected via a TFT to the data line located leftward of the column of sub-pixels. For example, each of the sub-pixels that constitute a first column is electrically connected via a TFT to the data line D1; each of the sub-pixels that constitute a second column is electrically connected via a TFT to the data line D2; and so on.
FIG. 2 is a schematic view showing a conventional data line share (DLS) TFT array substrate. The DLS TFT array substrate comprises data lines each corresponding two columns of sub-pixels and two scan lines respectively arranged above and below each row of sub-pixels. For sub-pixels of each row, a sub-pixel of an even column and a sub-pixel of an odd column that are respectively located on left and right sides of each data line are each electrically connected by a TFT to the data line, namely sharing the same data line. Also, for sub-pixels of each row, each of the sub-pixels of even columns is electrically connected by a TFT to the scan line above the row of the sub-pixels and each of the sub-pixels of odd columns is electrically connected by a TFT to the scan line below the row of the sub-pixels. For example, a second column and a third column of sub-pixels share the data line D2; a fourth column and a fifth column of sub-pixels share data line D3, and so on. Each of the sub-pixels of the first row that are in even columns is electrically connected by a TFT to the scan line G1 above the first row of sub-pixels and each of the sub-pixels of the first row that are in odd columns is electrically connected by a TFT to the scan line G2 below the first row of sub-pixels; each of the sub-pixels of the second row that are in even columns is electrically connected by a TFT to the scan line G3 above the second row of sub-pixels and each of the sub-pixels of the second row that are in odd columns is electrically connected by a TFT to the scan line G4 below the second row of sub-pixels, and so on. Compared to the traditional TFT array substrate shown in FIG. 1, the DLS TFT array substrate allows for reduction of the number of data lines by half and thus reduction of the cost; however, the number of scan lines is doubled so that the charging time that each sub-pixel may have is reduced by half due to the doubled number of scan lines and thus delays of signals in the corresponding data lines and scan lines would be more prominent. For example, at a tail end of a data line (or a scan line), the delay in the data line (or the scan line) could cause difference in charging rates between sub-pixels of the odd row and the sub-pixel of the even rows, and consequently, display defects of vertical bright and dark lines may result.
Specifically, reference is now made collectively to FIGS. 2, 3, and 4. As shown in FIG. 4, the manner of driving data lines is that polarity is reversed for every two dots. Due to RC delay, the data signals are not ideal square waves and the wave forms of the actual signals are wave forms with curved edges as shown in FIG. 3. For a specific sub-pixel Pxy, where x indicates the x-th row and y indicates the y-th column, such as sub-pixel P12 shown in FIG. 2 indicating a sub-pixel of the second column in the first row, when scan lines G1, G2, G3, G4, and so on are sequentially conducted on, the even-column sub-pixels would be sequentially driven earlier than the odd-column sub-pixels that are connected to the same data lines. For example, sub-pixels P12, P13, P22, P23 that are connected to the data line D2 are driven in that sequence. In the period of the same polarity of the data signal, the sub-pixel that is driven later is better charged than that driven earlier. As such, P13 is better charged than P12 and P23 is better charged than P22. After the reverse of polarity of the data signal, the driving sequence maintains the same, namely the even-column sub-pixels are driven first and then the odd-column sub-pixels are driven. As such, the even-column sub-pixels that are driven first may suffer being insufficiently charged so that the site corresponding to the even-column sub-pixels become insufficiently bright, making the overall displaying effect showing a defect of vertical bright and dark lines.